Dynamic Control Models of a Robot for High Speed and High Precision Assembly with Tolerance Constraints

A dynamic control model has been developed for robot motors controlling a high speed and high precision assembly process. This model includes the effects of parts tolerances and the tolerances of their associated assembly robots on assembly operations leading to the optimal allocation and distribution of tolerances to the workpieces and the robots. The application of modern control theory with constraints on state variables to the real time control of robots with displacement and motion constraints is generally difficult because of current limitations in controller processing time. The control model has been developed to facilitate the implementation of digital control algorithms using microprocessors with simple algebraic processing and yet satisfy robot constraints. Numerical examples are used to demonstrate the feasibility of the above near optimal control method. The simulation results show that high assembly speeds can be achieved with displacement, velocity and acceleration constraints and the computation required for real time implementation is relatively moderate.